<!DOCTYPE html>
<html>
<title>W3.CSS</title>
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="../lib/w3.css">
<body class="w3-container">
<h2>Active Accordions</h2>
<p>In this example we add the w3-red class to an active accordion (when the button is clicked on and the content is opened).</p>
<div class="w3-accordion w3-light-grey">
<button onclick="myFunction('Demo1')" class="w3-btn-block w3-left-align">Open Section 1</button>
<div id="Demo1" class="w3-accordion-content w3-container">
<p>Some text..</p>
</div>
<button onclick="myFunction('Demo2')" class="w3-btn-block w3-left-align">Open Section 2</button>
<div id="Demo2" class="w3-accordion-content w3-container">
<p>Some other text..</p>
</div>
</div>
<script>
function myFunction(id) {
var x = document.getElementById(id);
if (x.className.indexOf("w3-show") == -1) {
x.className += " w3-show";
x.previousElementSibling.className += " w3-red";
} else {
x.className = x.className.replace(" w3-show", "");
x.previousElementSibling.className =
x.previousElementSibling.className.replace(" w3-red", "");
}
}
</script>
</body>
</html>